Much attention has been given in recent years to the problem that when an item of merchandise is selected in a store, the price charged at checkout may differ from the price a customer expected to pay. This problem presents itself most prominently when a laser scanner is used at checkout, reading a uniform product code bar code and ringing up a price based on the contents of a database; if the contents of the database were to fail in some respect to match prices previously communicated to the customer (whether by product markings or by nearby shelf markings), then sooner or later a customer will be charged a price different from that which was expected.
One approach to this problem is to provide, within the store, a set of electronic price displays, one for each item of merchandise in the store. The information shown on the displays is desirably based on the same database that informs the checkout scanners, and barring equipment malfunction the price displayed at the shelf will be consistently identical to that charged at checkout.
The uninitiated might consider it to be a straightforward engineering matter to provide such a system of electronic price displays. Experience has uncovered many problems which do not yield to the first approach that might suggest itself. The solutions which one might try almost uniformly turn out to be prodigiously expensive to implement and discouragingly unreliable.
One family of difficulties relates to the selection of a communications architecture and topology by which a central computer or host may exchange messages with the multitude of electronic price displays (typically several tens of thousands) in a retail store. A number of engineering factors lead to a preferred topology that is tied to the physical layout of the store. A store generally has gondolas with shelves on each side, and the result as perceived by the customer is a number of aisles between the gondolas. In the preferred topology a central computer communicates with gondola controllers, one on each gondola. From a gondola controller a horizontal cable runs along the length of the gondola (typically along the top thereof). The gondola is made up of sections typically four feet long, and each section holds shelves that are typically four feet long. At each four-foot section, or at least at every other four-foot section, a vertical cable is installed. Each vertical cable is connected with the horizontal cable. On the front of each shelf a shelf rail is installed, and it is necessary to make some sort of connection with the vertical cable.
Many different cabling configurations have been attempted, as have many different connector technologies. None have heretofore been successful, however. In one technology, for example, at installation time the connections between shelf rails and the vertical rails have been accomplished by crimp-type connectors. This and most other technologies used heretofore have the drawback that if a shelf is to be moved subsequently (a not infrequent event in stores) it becomes necessary to make a connection at a different place on the vertical rail, requiring additional crimping activity at an awkward time and place.
It is also important to realize that while it may happen from time to time that one installs an electronic price display system in a store that is under construction, by far the more frequent business need is to install such a system in a store that is already in operation. Thus to be successful a technology must be workable despite a store's being in operation under circumstances where it is not easy to install any additional wiring, let alone wiring in the places that would be most convenient to the installer.
It is also important to realize that stores and gondolas differ greatly from one to the next in dimensions and design. As a result, it is desired to have a technology that is readily adaptable to the differing store and gondola circumstances.
Prior art technologies have the additional drawback that they are expensive to install. It will be appreciated that the number of electronic price displays in such a system is typically several tens of thousands, corresponding to the number of distinct store stock items. The number of shelf rails is perhaps one-fourth as many as the number of displays, but still in the thousands. Each shelf rail must be connected in some way with the central computer, so that the number of distinct connections to be made at installation time is linearly related thereto. Each connection must be easy, even for those with minimal training, must accommodate a variety of physical store shelf hardwares, and must be of inexpensive rather than exotic parts. Any cost-related or reliability-related misstep in design or materials selection is magnified thousandfold in the topology tied to shelf rails.
It is desirable to have a technology for store wiring that is easy to install by technicians of limited training, that accommodates store shelves that may or may not be empty or fully accessible, that is inexpensive to fabricate in the first place, and that uses commonly available materials and components to the extent possible. It is desirable to have a technology in which linearly disposed non-cable elements may be cut to length on site to fit actual store needs, and in which cabled elements do not require on-site labor-intensive cutting, shortening, or terminating steps, but which instead may be supplied with predetermined cable lengths and with design elements that dress and protect the cables, including any excess lengths. It is desired that the technology be robust against the hazards to which it is exposed, including the possibility of shorts due to errant surrounding materials. Finally, it is desirable to design in elements that minimize the possibility of inadvertent incorrect connections.